Rolling mill



March 7,1933. J ZAGORSKI AL 1,900,630

ROLLING MILL Filed Jan. 1929 3 Sheets-Sheet. 1

fig. 20

Mamh I933. J. ZAGORSKI El AL 3 ROLLING MILL Filed Jan. 2 1929 3 Sheets-Sheet 2 ,3 I I I I I I I 2 {I I J 4 I Is I 2 H I I I I I I I 3 l I I I 'I I I I a venlor;

March .7, 1933. ZAGORSK, ETAL 1,900,630

ROLLING MILL Fil ed Jan. 25, 1929 S SheetS-Sheet 3 I 1 fi Patented Mar. 7, 1933 UNITED STATES PATENT OFFICE J'OEANN ZAGOBSKI, OF FBANKFORT-ON-THE-MAIN, AND ERWIN W'ESNIGK, F BERLIN,

GERMANY i ROLLING mm.

Application filed January 2 5, 1929, Serial No.

In contradistinction to wood propellers, propellers of metal or other material adapted to be cast or forged have been mostly manufactured as hollow propellers composed of several parts or as solid propellers cut out from sheets, which near the hub need a large breadth for sustaining the forces, but nevertheless have no suflicient rigidity against torsional stresses. 4 The 1nvent1on consists 1n forming a propeller of metal or other deformable material with a hub of suflicient dimensions for the transmission of the forces and for immediate mounting on the shaft, and with blades having thick profiles near said hub and fiat profiles on their main length. Entire propellers or single blades for composing three or four bladed propellers or variable pitch propellers can be produced in this manner, and a good efiiciency is secured in all cases.

For the production of the new propeller the invention concerns a rolling process and a special rolling mill, wherein the entire propeller or a propeller blade is rolled down outof a warm block of material so as to have in all parts the right profiles and near the hub also the right pitches, Whereas the pitches on the outer blade parts are regulated by twisting the blades in cold state.

Several details are further concerned in the invention as later described.

The invention is illustrated on the drawings, in which:

Fig. 1 is an axial view and propeller, partially in section,

Figs. 3 and 4 are similar views of a threebladed hub part, 40 Figs. 5 and 6 are similar views of a fourbladed hub part,

Figs. 7 and 8 are similar views of a fourbladed hub part of another embodiment.

Figs. 9 and 10 are a cross view and a lateral 45 view of a cast block for several two-bladed propellers,

Fig. 2 a transverse view of a two-bladed aaspso, and in Germany 1 cember 17, 1927.

Figs. 11 and 12 are a'lateral view and an axial view of a cast block for a single two bladed propeller,

Figs. 13 and 14 are cross sections corresponding to the lines XIIIXIII and XIV-XIV of Fig. 11 respectively,

Fig. 15 is a modified embodiment of the cross section shown in Fig. 14,

Figs. 16, 17 and 18 are respectively a 1ongitudinal view, a transverse view and a top view of a rolling mill for producing. the propellers.

Fig. 19 is a detail transverse sectional view on the plane indicated by the line XIXXIX of Fig. 1. 60

Fig. 20 is a similar view on the plane indicated by the line XXXX of Fig. 1.

Fig. 21 is a similar view on the plane indicated by the line XXI-XXI of Fig. 1.

Fig. 22 is asimilar view on the plane indicated by the line XXII-XXII of Fig. 1.

Fig. 23 is a similar view on the plane indicated by the line XXIII-XXIII of Fig. 1.

Fig. 24 is a similar view on the plane indicated by the line XXIVXXIV of Fig. 1.

Fig. 25 is a similar view on the lane indicated by the line XXVXXV of Fig. 1.

According to Figs. 1 and 2 the propeller is provided with a hub 1, whose cross-section is sufiicient to sustain the centrifugal and torsion stresses by complete utilization of the strength of the material used, which particularly is a refinable alloy of aluminium or magnesium. From this hub part, bladeshafts 2 extend, which have short thickstream-lined profiles, as designed, and are arranged with angles corresponding to the pitch of the propeller. Further the blades 3 are enlarged against the ends and shaped to a usual blade contour, the profiles being thin so as to be aerodynamically favourable and have still sufiicient resistance against torsion.

All profiles are positioned under oblique pitch angles in usual manner, but this is not shown for matter of simplicity. For balancing the strains arising from the thrust the straight lined shape shown in Fig. 2 may be modified to a forward bentshape following the line resultant from thrust and centrifu-' are preformed ,in similar shape, the blade feet 2 extending from hub sectors 1, which -by dove tailed or zig-zagged radial surfaces 4 are centered on each other and are secured together by clamping rings 5 embedded in their end faces. The said rings 5 may be shrunk on their seats or fastened under tension in any other way and are held by screw bolts 6.

According to Figs. 5 and 6 a four bladed propeller is composed in a similar manner. The dove tailed or zig-zagged projections 4 of the radial surfacesare here disposed axial ly. For securing the parts together, discs 5 are provided, one of which is formed as a flange of the propeller shaft.

According to Figs. 7 and 8 a four bladed propeller is formed with radial projections 4 of the contacting radial surfaces of the sectors, and the parts are secured together by clamping discs 5' and bolts 6; The clamping discs 5' serve at once for holding a head cap 7 of the hub and an annular 8 leading to the motor or gear case.

According to Figs. 9' and 10 for the production of two bladed propellers of small sizes and in great numbers, a cast block is employed, of which the part corresponding to the hub 1 and to the blade feet 2 is thinner than the parts corresponding to the blades 3. Said block is cut at 9' into parts, each of which has the described profile and serves as a plurality of blades aseparately cast blockraw block to be milled. 4

In the case of propellers with a plurality of blades according to Figs. 3-8, a similar block is employed, in which from the hub part 1- only to one direction a part corresponding to the blade feet 2 and blades 3 is extended. I

According to Figs. 11 and 12, for large specially heavily loaded two blade propellers or separate blades ofpropellers'with is employed, in which the hub part 1 has already the round shape, and also the blade feet 2 and blades 3 have already approximately the final profiles and pitch angles so that the further work here extends essentially only to the longitudinal stretching of the blades by milling. For a specially good preparation the blades have the profiles shown in Figs. 13 and 14:, whereas for a simpler process the cross section near the hub can be chosen as shown in Fig. 15.

For rolling or milling the described blocks,

v according to Figs. 1618 a rolling mill is used,

the thick parts which contains an upper roll 111a lower roll 12 and a roll table 13 arranged for easy movement in the direction of rolling. The

upper roll 11 is shaped in its circumference as a; die or mould corresponding to whole propeller (or a single propeller blade),'confined by a line following the contour along the entering and trailing edges of the blades and an adapted connecting line on the hub. If single blades are to be rolled the hub die has advantageously the diagonal arrangement shown by dotted lines at 15 in Fig. 16,

so that a diagonal plane of the hub and the blade are essentially parallel to axes of the rolls. The lowerroll 12 and the table 13 together contain the remaining part of the die, the table being provided with a longitudinal slot 16, into which projects a. die

part 17 of the lower roll 17. The dies of both rolls and of the tableare preferably so shaped as to produce immediately the final profiles and pitch angles of the propeller or propeller blade, but it is also possible with advantage, to simplify the die so as to' roll only near the nave the same pitch angle and are formed as plane parts. The, final pitch angles, which decrease against 'the blade tips, are then ad usted afterwards by twisting the blades in cold 22 of the said lower shaft 19 are in engagement with toothed racks 23 provided on the the final pitch angles, 9

whereas the remaining blade parts receive table 13 so as to drive the latter. All toothed wheels are so adjusted that precisely corresponding parts of the lower and u per .rolls end of the table work together. blique or for securing uniform running. The bearmgs of the upper roll are adjustable in height-by aid of spindles 24, on which conical wheels 25 run by screw threads, and said wheels 25 are in engagement on a common driving arrow shaped teeth are preferably employed to the material are excluded, as only the thinner outer blade parts need very precise pitch angles, but these can be adjusted with small and innoxious deformations. The use of a raw block having already a half finished shape has the advantage that the blades essentially need only to be stretched in their longitudinal direction, so that no splitting of the material occurs, which otherwise would arise especially with refined aluminium or its alloys or with other materials of low ductility. This advantage is attained for small propellers already by the use of a common block out into several pieces for the production'of several propellers, and with special advantage the separate blocks used for large propellers avoid funnels to be included in the raw blocks and excessive rolling strains to arise-in the material.

In the rolling mill, the use of the roll table in connection with an upper roll secures a rolling operation without undue bending of the propeller, so that propellers with straight lined center line or with a bend according to the resultant from thrust and centrifugal force can be very precisely produced. Thereby a good balance of the forces and masses in the use of the propeller is attained without the aid of costly finishing work. The table can serve as a complete lower die, but the auxiliary use of the lower roll ensures the material to be essentially equally rolled and stretched on both sides, so that it assumes a uniform distribution of its longitudinal fibres and a uniform elasticity.

If entire twobladed propellers are to be rolled, the dies are-so shaped, that the hub plane lies parallel to the table, and the blade cross sections lie obliquely to the table so as to have the right pitches at least on the thick parts near the nave. We claim: 1. A rolling mill for rolling molded propellers, comprising in combination a roll table having a longitudinal slot, an upper roll arranged above said table, a lower roll so arranged as to project through said slot, and agear connecting said table and said rolls for common movement, said upper roll, lower roll and table each containing a die cavity which cavities coact to form the propeller blade.

2. A rolling mill for rolling molded propellers, comprising in combination a roll table having a longitudinal slot, an upper roll arranged above said table, a lower roll so ar-' ranged as to project through said slot, means for driving said lower roll, and a gear for driving said table and upper roll from said lower roll, said upper roll, lower roll and table each containing a die cavity which cavities coact to form the propeller blade.

3. A rolling mill for rolling molded propellers, comprising, in combination, a roll table having a longitudinal slot, an upper roll arranged above said table, a lower roll arranged below said table, means for sup orting said table so as to be slidable tangentially In witness whereof we aflix our signatures.

. J OHANN ZAGORSKI.

ERWI'N WESNIGK. 

